For example, in a mixed reality presentation system, wherein a real world and virtual world are merged in a three-dimensionally matched form, the depth (front and behind) ordering of real objects and virtual objects must be correctly recognized to render the virtual objects in a form that does not conflict with that depth ordering. For this purpose, depth information (three-dimensional information) of the real world must be acquired.
EP 0 955 606 describes a depth image measurement apparatus for acquiring depth information of a scene. The depth image measurement apparatus comprises means for inputting an image of a scene at a first viewpoint and depth image generation means for generating a first depth image from the scene image inputted at the first viewpoint by said image input means. The apparatus further comprises position/posture estimation means for estimating a position and posture information at a second viewpoint viewed from a position and posture of the first viewpoint. The apparatus further comprises warping means for warping the first depth image generated by said depth image generation means to a second depth image at the second viewpoint estimated by said position/posture estimation means.